Flynn was reportedly a top candidate for the position and was said to be Trump's choice after the pair met on Wednesday.

Flynn has held a number of military roles throughout his career, serving as the director of the Defense Intelligence Agency and chair of the Military Intelligence Board.

In July, the retired lieutenant general emerged as one of the top potential candidates to become Trump's vice presidential pick.

Throughout Trump's campaign, Flynn also served as a military adviser, giving Trump advice on questions of foreign policy and military strategy.

Jason Miller, an aide to Trump, foreshadowed the announcement on Wednesday, stating that Flynn would be a "fantastic" candidate for the position.

"He'd be a fantastic addition. I'll let the president-elect make that decision. I'm a huge fan of Gen. Flynn," he said in an interview with Fox News's Megyn Kelly.

Flynn is the first major Trump appointment since he chose Steve Bannon as his top strategist and Reince Priebus as chief of staff. It's not clear if Flynn has accepted the position. The job does not require confirmation by the Senate.